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Need help - NP208 speedo gear removal (read last post)

A 208 is not too bad. Grab a manual that explains the teardown and take a look at it to see if you feel comfortable. The only tricky part in assembly is a set of needle bearings - but they can be held in place nicely with petroleum jelly. IIRC you need a large snap ring separator for something. If you already have it out, you might as well tear it down before you order parts.

There are write-ups here if you do a search. Worst case is that you carry it to a driveline shop in a box. You already saved the labor cost of getting it out of the vehicle.
 
I had time yesterday to split the case and have a look inside. Everything that I could see looked okay, but lying in the bottom of the case was a metal washer about 1.5" in diameter with about a 3/8" hole in the middle of it. It's obviously steel because it had chunks of metal and needle bearings magnetized to it. I can't see where it came from without disassembling the whole thing. Not good. I didn't have a chance to go any further because it started to rain and didn't stop literally all day. (I only have an outside workspace.) Oh yeah, there were also some black plastic shavings lying on the needle bearings for the rear end of the front output gears. I'll post some pics when it stops raining.

I really would like to have a good service manual in hand before I go tearing this thing down so I'll know exactly what I'm up against. Where can I get one from?
 
I think you found the magnet that goes at the bottom of the t-case if you are finding needle bearings at the bottom there is a chance the needle bearing that goes between the planetary and case fell apart which normally damages the case. When it fails it lets the planetary move back and forth and yours may have jambed on the case locking it solid. The plastic pieces are the nylon pads that go on the range fork at the bottom of the case this is the fork that gives you hi/lo in the t-case and it is located right behind the planetary. I will bet the case is junk due to the surface that the needle bearing in the front of the case being torn-up by the planetary.
 
bigred81 said:
I think you found the magnet that goes at the bottom of the t-case if you are finding needle bearings at the bottom there is a chance the needle bearing that goes between the planetary and case fell apart which normally damages the case. When it fails it lets the planetary move back and forth and yours may have jambed on the case locking it solid. The plastic pieces are the nylon pads that go on the range fork at the bottom of the case this is the fork that gives you hi/lo in the t-case and it is located right behind the planetary. I will bet the case is junk due to the surface that the needle bearing in the front of the case being torn-up by the planetary.
Click to expand...

Hey thanks for that info. You really helped me out a lot there. This will get me moving in the right direction.

As I mentioned before, someone offered to sell me an NP208 from a military Blazer. Someone replied that the Blazer used a TH400 tranny and therefore had a different input spline count. Would it be possible to use that case for parts to fix mine? If my case is junk, could I swap some stuff around to make the one from the Blazer work in my truck?
 
If your input gear is good, it can be swapped into another 208 - or even the whole planetary set. Which means you still need to complete the teardown of that case to know what you are dealing with.
 
Make sure and take pictures of everything you do....if possible.

It's a great reference for putting it back together.
 
I agree, do a writeup and lots of pics, i want to tear down my 208 as well but ive heard the 241 is easier to dissasemble due to the bearings and i already found a good writeup on it
 
This is what I found stuck to the magnet in the bottom of the case.

P1190179.jpg



th_P1190179.jpg


Looks like some needle bearings and some chunks of metal off the bearing. I'll take the whole thing apart this weekend hopefully. The macro mode wasn't working on my camera. That's why the fullsize pic is so fuzzy. I'll try to figure that one out.
 
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I think those bearings are for the chain sprocket on the main shaft. Hopefully they aren't both trashed.

2589d1173545088-np-208-rebuild-np208.jpg


np208mw_large.jpg
 
Which number in the drawing is the bearing for the chain sprocket on the main shaft? 73? Thanks for the exploded view, by the way. It seems to be backwards from mine. Probably because it's a Ford case. I guess everything inside would be about the same, right? Where did you source that drawing, Blue85?
 
Don't worry if the diagram is PSD or DSD - the parts will still go together in the same order. Pics are easy to find: http://www.google.com/images?um=1&hl=en&biw=1680&bih=965&tbs=isch:1&sa=1&q=np208+exploded&aq=f&aqi=&aql=&oq=

I was thinking that there were teardown instructions in the Chilton manual for 80's trucks. Maybe somebody else can confirm/deny.

This one looks like a Dodge, but at least includes the part names:

NP208_exploded.gif



You can get the pdf version here: www.partesymas.com/catalogos/4x4/NP208.pdf
 
Once again, thanks for the drawings. You are the man. I had some time today to take some of the guts out and look at them. I found a huge crack in the planetary assembly. I took a picture, but it turned out real fuzzy because I couldn't really get the camera in the right position.

P1200217.jpg
 
I have seen several 208 tcases where the planetary just exploded and locked up the transfer case. Many of them were in trucks used in the oil field were they were used very hard and often due to some of the roads they had to drive on to get to the drilling platform.
 
bigred81 said:
I have seen several 208 tcases where the planetary just exploded and locked up the transfer case. Many of them were in trucks used in the oil field were they were used very hard and often due to some of the roads they had to drive on to get to the drilling platform.
Click to expand...

Yesterday afternoon I had a chance to start taking the guts out and take a look at them. I took a bunch of pics and tried to post them but the sorry computer crapped out and I just got mad and went to bed. I did find the damage though. The planetary was cracked big time. Actually it was more like split in two. Tell you the truth, I'm not sure I want to put this thing back under my truck. I'm only running a stock 305 with 35" BFGs and I'm not the type to just stand on the gas or anything like that, and yet this t-case can't even handle mild trails. It may be time to go to an NP205 and TH400 or something like that. What do you fellas think? I'll try again today after work to post the carnage pics.
 
Depending upon the type of terrain you run.....I would think about some other option than a 205. They are strong, but the gear ratio sucks. I ran TH350/NP205 w/ 4.56 gears and 35" tires and pretty much rode the brakes all the time going downhill. I suppose ok for minor trails, but I would not swap in a 205.

my $.02
 
Stick with the 208, light weight, nice low gear ratio, strong, (as long as you protect the case from impact). Your broken planetary is probably one of those fluke things that happens and was not related to power/abuse.
 
That makes me feel somewhat better. Guess I'll stick with the current case. What about the NP241 though? Isn't it supposed to be a better case? Is it a bolt-in as long as it has a speedo cable and not TPS? Would it be a better option than keeping the 208?
 
This fuzzy pic is of the crack in the bottom of the planetary assembly. It won't let anything move on that side.

th_P1200217.jpg
 
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